Compound, nanoribbon, and semiconductor device

ABSTRACT

A nanoribbon includes a structure represented by a structural formula (8), where g, p, q, r, s, t, and u are mutually independent and are integers greater than or equal to 1, R1, R2, R3, R4, R5, R6, R7, and R8 are mutually independent and are one of a hydrogen atom, a substituent, an alkyl moiety, a phenyl moiety, and a halogen atom, and A denotes a hydrogen atom or an aryl group.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Division of U.S. patent application Ser. No. 16/777,450 filedJan. 30, 2020, now U.S. Pat. No. 11,401,291, which claims priority under35 U.S.C. Section 119 to Japanese Patent Application No. 2019-036472filed on Feb. 28, 2019, the entire contents of which is hereinincorporated by reference.

FIELD

The embodiments discussed herein are related to a compound, ananoribbon, and a semiconductor device.

BACKGROUND

Graphene, which is a two-dimensional material having an extremely highcharge mobility, is regarded as a material that may overcome refininglimits of Large Scale Integrated (LSI) circuits. Because the graphenehas a high mobility of approximately 100,000 cm²/Vs at room temperatureand the electron mobility and the hole mobility do not differ, thegraphene is expected for use as a channel material of future electronicdevices. However, since the graphene has no band gap, the graphene as itis has a small on-off ratio, thereby making it difficult for use inswitching elements.

On the other hand, in nano-sized graphene, a difference between thenumber of C atoms at the edge and the number of C atoms on the innerside of the edge is small, and the effects of the shape of the grapheneitself and the shape at the edge are large, thereby making the grapheneexhibit characteristics that differ greatly from the characteristics ofbulk graphene. Known nano-sized graphenes include a ribbon-shapedquasi-one-dimensional graphene having a width of several nm, such as theso-called Graphene Nano-Ribbon (GNR). For example, the GNR may besynthesized by polymerizing a precursor compound. This method ofsynthesizing the GNR may be referred to as the bottom-up synthesis orthe bottom-up technique. The characteristics of the GNR greatly changedepending on the edge structure and the ribbon width.

The edge structure of the GNR includes two kinds, namely, the arm-chairedge in which the C atoms are arranged at a period of 2 atoms, and thezigzag edge in which the C atoms are arranged in a zigzag. In thearm-chain edge type GNR (AGNR), a finite number of band gaps spread dueto the quantum-confined effect and the edge effect, causing the AGNR toexhibit semiconductor-like properties. On the other hand, the zigzagtype GNR (ZGNR) exhibits metal-like properties.

The characteristics of the GNR greatly change also depending on the edgemodifier. Hence, a heterojunction semiconductor device has been proposedin which the edge modifier bonds different GNRs.

However, electron states of the GNRs manufactured using conventionalprecursor molecules are limited, and it is difficult to produce variouselectron states. For example, it is difficult to vary the conductivitytype and the band gap of the conventional GNRs.

Further, nanoribbons including continual porphyrin rings, calledporphyrin tapes or tape porphyrin, are also known. However, it is alsodifficult to vary the conductivity type and the band gap of thenanoribbons.

Applicants are aware of the following documents.

Japanese Laid-Open Patent Publication No. 2007-027190

Japanese Laid-Open Patent Publication No. 2007-194360

Japanese Laid-Open Patent Publication No. 2016-090510

Japanese Laid-Open Patent Publication No. 2015-191975

Japanese Laid-Open Patent Publication No. 2016-194424

Jinming Cai et al., “Atomically precise bottom-up fabrication ofgraphene nanoribbons”, Nature, Vol. 466, 22 July 2010, pp. 470-473

Akihiko Tsuda et al., “Fully Conjugated Porphyrin Tapes with ElectronicAbsorption Bands That Reach into Infrared”, Science, Vol. 293, 6 Jul.2001, pp. 79-82

Tien Quang Nguyen et al., “Adsorption of diatomic molecules on irontape-porphyrin: A comparative study”, Physical Review, B 77, 195307,2008, pp. 1-7

SUMMARY

Accordingly, it is an object in one aspect of the embodiments to providea compound, a nanoribbon, and a semiconductor device, which can obtainvarious electron states.

According to one aspect of the embodiments, a compound is represented bya structural formula (1) or a structural formula (2), where p, q, r, s,t, and u are mutually independent and are integers greater than or equalto 1, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ are mutually independent andare one of a hydrogen atom, a substituent, an alkyl moiety, a phenylmoiety, and a halogen atom, and A denotes a hydrogen atom or an arylgroup.

According to another aspect of the embodiments, a method ofmanufacturing a compound includes coupling a first compound representedby a structural formula (3), a second compound represented by astructural formula (4), and a third compound represented by a structuralformula (5), to synthesize a fourth compound represented by a structuralformula (6), where p, q, r, s, t, and u are mutually independent and areintegers greater than or equal to 1, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸are mutually independent and are one of a hydrogen atom, a substituent,an alkyl moiety, a phenyl moiety, and a halogen atom, and A denotes ahydrogen atom or an aryl group.

According to a further aspect of the embodiments, a nanoribbon includesa structure represented by a structural formula (8) or (9), where g orh, p, q, r, s, t, and u are mutually independent and are integersgreater than or equal to 1, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ aremutually independent and are one of a hydrogen atom, a substituent, analkyl moiety, a phenyl moiety, and a halogen atom, and A denotes ahydrogen atom or an aryl group.

According to another aspect of the embodiments, a nanoribbon includes afirst unit having a structure including an arrangement of a plurality offirst sub-units respectively including a structure represented by astructural formula (10); and a second unit having a structure includingan arrangement of a plurality of second sub-units respectively includinga structure represented by a structural formula (11) or (12), whereinthe first unit and the second unit are mutually bonded by acarbon-to-carbon bonding between an end of the first unit and an end ofthe second unit, and wherein M₁ denotes a metal atom or M₁ and M₂ denotemutually different metal atoms, and A denotes a hydrogen atom or an arylgroup.

According to still another aspect of the embodiments, a method ofmanufacturing a nanoribbon, includes generating a dehalogenationreaction in the compound referred above, to obtain a polymer; andgenerating a dehydrocyclization reaction in the polymer.

According to a further aspect of the embodiments, a semiconductor deviceincludes a substrate; the nanoribbon referred above and provided on thesubstrate; source and drain electrodes provided on the nanoribbon atrespective ends of the nanoribbon; an insulating layer provided on thenanoribbon; and a gate electrode formed on the insulating layer at aposition between the source and drain electrodes.

The object and advantages of the invention will be realized and attainedby means of the elements and combinations particularly pointed out inthe claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and arenot restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating GNR according to a first embodiment;

FIG. 2A is a diagram illustrating a band structure of the GNR accordingto the first embodiment;

FIG. 2B is a diagram illustrating a band structure ofhydrogen-terminated GNR;

FIG. 3 is a diagram illustrating the hydrogen-terminated GNR;

FIG. 4A is a diagram for explaining a method of manufacturing the GNRaccording to the first embodiment;

FIG. 4B is a diagram for explaining the method of manufacturing the GNRaccording to the first embodiment;

FIG. 5 is a diagram illustrating a method of manufacturing precursormolecules used for manufacturing the GNR according to the firstembodiment;

FIG. 6 is a diagram illustrating the GNR according to a secondembodiment;

FIG. 7A is a diagram illustrating a band structure (M═Zn) of the GNRaccording to the second embodiment;

FIG. 7B is a diagram illustrating a band structure (M═Cu) of the GNRaccording to the second embodiment;

FIG. 7C is a diagram illustrating a band structure (M═Ni) of the GNRaccording to the second embodiment;

FIG. 8A is a diagram illustrating the method of manufacturing the GNRaccording to the second embodiment;

FIG. 8B is a diagram illustrating the method of manufacturing the GNRaccording to the second embodiment;

FIG. 9 is a diagram illustrating the method of manufacturing theprecursor molecules used for manufacturing the GNR according to thesecond embodiment;

FIG. 10 is a diagram illustrating the GNR according to a thirdembodiment;

FIG. 11A is a diagram illustrating the method of manufacturing the GNRaccording to the third embodiment;

FIG. 11B is a diagram illustrating the method of manufacturing the GNRaccording to the third embodiment;

FIG. 12 is a diagram illustrating the GNR according to a fourthembodiment;

FIG. 13A is a diagram illustrating the method of manufacturing the GNRaccording to the fourth embodiment;

FIG. 13B is a diagram illustrating the method of manufacturing the GNRaccording to the fourth embodiment;

FIG. 14 is a diagram illustrating a nanoribbon according to a fifthembodiment;

FIG. 15A is a diagram illustrating the method of manufacturing thenanoribbon according to the fifth embodiment;

FIG. 15B is a diagram illustrating the method of manufacturing thenanoribbon according to the fifth embodiment;

FIG. 16 is a diagram illustrating the nanoribbon according to a sixthembodiment;

FIG. 17A is a diagram illustrating the method of manufacturing thenanoribbon according to the sixth embodiment;

FIG. 17B is a diagram illustrating the method of manufacturing thenanoribbon according to the sixth embodiment;

FIG. 18A is a plan view illustrating a semiconductor device according toa seventh embodiment;

FIG. 18B is a cross sectional view illustrating the semiconductor deviceaccording to the seventh embodiment;

FIG. 19 is a diagram illustrating the band structure of the GNR includedin the semiconductor device according to the seventh embodiment;

FIG. 20A is a cross sectional view illustrating a method ofmanufacturing the semiconductor device according to the seventhembodiment;

FIG. 20B is a cross sectional view illustrating the method ofmanufacturing the semiconductor device according to the seventhembodiment;

FIG. 20C is a cross sectional view illustrating the method ofmanufacturing the semiconductor device according to the seventhembodiment;

FIG. 20D is a cross sectional view illustrating the method ofmanufacturing the semiconductor device according to the seventhembodiment;

FIG. 21A is a plan view illustrating the semiconductor device accordingto an eighth embodiment;

FIG. 21B is a cross sectional view illustrating the semiconductor deviceaccording to the eighth embodiment;

FIG. 22 is a diagram illustrating the band structure of the GNR includedin the semiconductor device according to the eighth embodiment;

FIG. 23A is a cross sectional view illustrating a method ofmanufacturing the semiconductor device according to the eighthembodiment;

FIG. 23B is a cross sectional view illustrating the method ofmanufacturing the semiconductor device according to the eighthembodiment;

FIG. 23C is a cross sectional view illustrating the method ofmanufacturing the semiconductor device according to the eighthembodiment.

FIG. 23D is a cross sectional view illustrating the method ofmanufacturing the semiconductor device according to the eighthembodiment.

DESCRIPTION OF EMBODIMENTS

Preferred embodiments of the present invention will be described withreference to the accompanying drawings.

A description will now be given of a compound, a nanoribbon and asemiconductor device according to each embodiment of the presentinvention.

First Embodiment

A first embodiment will be described. The first embodiment relates toGraphene Nano-Ribbon (GNR). FIG. 1 is a diagram illustrating the GNRaccording to the first embodiment.

GNR 100 according to the first embodiment has a structure in whichsub-units 113, each including 2 rows of anthracene 112 bonded to aporphine ring 111, are arranged as illustrated in FIG. 1 . In otherwords, the GNR 100 has a structure in which each of p, q, r, s, t, and uis 1, each of R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁶ is hydrogen (H), and Ais H in the above-mentioned structural formula (9). The GNR 100 includesa chemical structure of porphyrin.

Next, a band structure of the GNR 100 will be described. FIG. 2A andFIG. 2B are diagrams illustrating band structures of GNRs predictedaccording to computations employing a first principle. FIG. 2Aillustrates the band structure of the GNR 100, and FIG. 2B illustratesthe band structure of a hydrogen-terminated GNR 150.

As illustrated in FIG. 2B, the hydrogen-terminated GNR 150 illustratedin FIG. 3 exhibits properties of an intrinsic (i-type) semiconductor,and the band gap thereof is 1.6 eV. On the other hand, as illustrated inFIG. 2A, the GNR 100 exhibits properties of the intrinsic (i-type)semiconductor, and the band gap thereof is 0.5 eV which is less than ⅓the band gap of the hydrogen-terminated GNR 150. Hence, the GNR 100 haselectron states different from those of the hydrogen-terminated GNR 150,and can contribute to producing various electron states. Further, theGNR 100 has good application properties with respect to varioussemiconductor devices.

Next, a method of manufacturing the GNR 100 will be described. FIG. 4Aand FIG. 4B are diagrams illustrating, in sequence, processes of themethod of manufacturing the GNR 100.

First, a precursor molecule 120 illustrated in FIG. 4A is prepared. Theprecursor molecule 120 is represented by the following structuralformula (1′). In the precursor molecule 120, X denotes a halogen atom,such as a bromine (Br) atom, for example, that is bonded to a tenthcarbon atom 130 of anthracene 122. A ninth carbon atom 129 of theanthracene 122 is bonded to a porphine ring 121.

Then, the precursor molecules 120 are deposited on a (111) face of aheated catalyst metal substrate by vacuum deposition. A substrate madeof gold (Au), silver (Ag), copper (Cu), or the like may be used for thecatalyst metal substrate. The precursor molecules 120 may be depositedon a (110) face or a (100) face of the catalyst metal substrate byvacuum deposition, or may be deposited on a crystal face of a higherindex, such as a (788) face or the like, by vacuum deposition. Whenusing a (111) face of the Au substrate (hereinafter also referred to asthe “Au(111) face”) as a depositing surface, the temperature of theAu(111) face, cleaned in ultra-high vacuum, is maintained toapproximately 200° C. to approximately 300° C., for example, and theprecursor molecules 120 are deposited by the vacuum deposition. Theamount that is deposited in this state is preferably adjusted to becomeapproximately 1 molecular layer. In this temperature range, adehalogenation reaction is generated in which desorption of hydrogenbromide (HBr) occurs between the precursor molecules 120 adsorbed on theAu (111) face, to promote polymerization of the precursor molecules 120(or precursor molecule group). As a result, a polymer 140 illustrated inFIG. 4B is formed.

Thereafter, the Au (111) face having the polymer 140 formed thereon isheated under vacuum to a high temperature of approximately 350° C. toapproximately 450° C., for example. In this high temperature range, adehydrocyclization reaction is generated in which desorption of hydrogen(H₂) occurs within the precursor molecules 120 and between the precursormolecules 120 in the polymer 140, to promote aromatization. As a result,the GNR 100 according to the first embodiment is formed.

Hence, the GNR 100 according to the first embodiment can be manufacturedby the bottom-up synthesis.

Next, a method of manufacturing the precursor molecules 120 will bedescribed. FIG. 5 is a diagram illustrating the method of manufacturingthe precursor molecules used for manufacturing the GNR. First, in thismanufacturing method, aryl groups 151 and 152 respectively includinghalogen moieties and formyl groups, and 2,2′-dipyrromethane 153, arestirred in an organic solvent, and an acid is thereafter added togenerate a condensation reaction. Next, an oxidizing agent (or oxidant)is added, and stirred at room temperature or stirred while applyingheat, to advance oxidation. As a result, porphyrin 154 is obtained.

In FIG. 5 , X denotes a halogen atom, p, q, r, s, t, and u are mutuallyindependent and are integers greater than or equal to 1, R¹, R², R³, R⁴,R⁵, R⁶, R⁷, and R⁸ are mutually independent and are one of a hydrogenatom, a substituent, an alkyl moiety, a phenyl moiety, and a halogenatom, and A denotes a hydrogen atom or an aryl group. The integers p, q,r, s, t, and u may be mutually different or, 2 or more integers amongthese integers p, q, r, s, t, and u may be the same. The R¹, R², R³, R⁴,R⁵, R⁶, R⁷, and R⁸ may be mutually different or, 2 or more among theseR¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ may be the same. The alkyl moiety andthe phenyl moiety among the R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ mayinclude a substituent. The alkyl moiety may be straight-chained orbranch-chained. The carbon number of the alkyl moiety may be 1 to 20,for example. Examples of the alkyl moiety include a methyl group, anethyl group, a propyl group, an isopropyl group, a butyl group, anisobutyl group, a sec-butyl group, and a tert-butyl group, for example.Examples of the substituent include a hydroxyl group, a nitro group, anamino group, a formyl group, a carboxyl group, and a sulfonyl group, forexample. Examples of the halogen atom include a fluorine atom, achlorine atom, a bromine atom, and an iodine atom, for example. The arylgroup A may include a substituent.

Examples of the organic solvent that may be used include a mixture of ahalogen-based solvent, such as dichloromethane, chloroform, or the like,that is added with an acid catalyst, for example. Examples of the acidcatalyst that may be used include chloranil, trifluoroacetate, propionicacid, 2,3-dichloro-5,6-dicyano-p-benzoquinone, or the like, for example.Examples of the acid that may be used include trifluoroacetate, borontrifluoride-diethyl ether complex, and propionic acid, for example.Examples of the oxidizing agent that may be used include chloranil or2,3-dichloro-5,6-dicyano-p-benzoquinone, or the like, for example.

When manufacturing the precursor molecule 120, compounds in which eachof the integers p, q, r, s, t, and u is 1, and each of the R¹, R², R³,R⁴, R⁵, R⁶, R⁷, and R⁸ is H in the above-mentioned structural formulas(3) and (4), may be used for the aryl groups 151 and 152. In otherwords, the aryl groups 151 and 152 may be represented by the followingstructural formula (3′). In addition, a compound in which the aryl groupA is H may be used for the 2,2-dipyrromethane 153. In other words, the2,2-dipyrromethane 153 may be represented by the following structuralformula (5′).

In the following description, a GNR in which the structures representedby the above-mentioned structural formula (11) are arranged, may also bereferred to as a porphyrin GNR.

In the above-mentioned structural formulas (9), (3), (4), and (11), theintegers p, q, r, s, t, and u may be mutually independent and beintegers greater than or equal to 2, the R¹, R², R³, R⁴, R⁵, R⁶, R⁷, andR⁸ may be mutually independent and be any one of a substituent, an alkylmoiety, a phenyl moiety, and a halogen atom, and the alkyl group A maybe an aryl group.

Second Embodiment

Next, a second embodiment will be described. The second embodimentrelates to the GNR. FIG. 6 is a diagram illustrating the GNR accordingto the second embodiment.

A GNR 200 according to the second embodiment has a structure in whichsub-units 213, each including 2 rows of anthracene 212 bonded to aporphine ring 211 that includes a metal atom M₁, are arranged asillustrated in FIG. 6 . In other words, the GNR 200 has a structure inwhich each of the integers p, q, r, s, t, and u is 1, each of the R¹,R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ is hydrogen (H), and the alkyl group A isH in the above-mentioned structural formula (8). The metal atom M₁ is anatom of magnesium (Mg), iron (Fe), cobalt (Co), nickel (Ni), titanium(Ti), copper (Cu), zinc (Zn), or the like, for example. The metal atomM₁ is not limited to the atom of these elements, as long as the metalatom M₁ can be coordinated in a porphyrin ring. The GNR 200 includes achemical structure of a metallic complex of porphyrin.

Next, a band structure of the GNR 200 will be described. FIG. 7A through7C are diagrams illustrating band structures of GNRs predicted accordingto computations employing the first principle. FIG. 7A illustrates theband structure of the GNR 200 for a case where the metal atom M₁ is theZn atom, FIG. 7B illustrates the band structure of the GNR 200 for acase where the metal atom M₁ is the Cu atom, and FIG. 7C illustrates theband structure of the GNR 200 for a case where the metal atom M₁ is theNi atom.

As illustrated in FIG. 7A, in the case where the metal atom M₁ is the Znatom, the GNR 200 exhibits properties of the intrinsic (i-type)semiconductor, and the band gap thereof is 0.5 eV which is less than ⅓the band gap (1.6 eV) of the hydrogen-terminated GNR 150. As illustratedin FIG. 7B and FIG. 7C, in the cases where the metal atom M₁ is the Cuatom and the Ni atom, respectively, a Fermi level E_(F) is higher than abottom of a valence band thereof, and the GNRs 200 exhibit properties ofan n-type semiconductor. Hence, the GNR 200 has electron statesdifferent from those of the hydrogen-terminated GNR 150, and differentconductivity types and band gaps are obtained according to the kind ofmetal used for the metal atom M₁. Accordingly, the GNR 200 cancontribute to producing various electron states, and the GNR 200 hasgood application properties with respect to various semiconductordevices.

Next, a method of manufacturing the GNR 200 will be described. FIG. 8Aand FIG. 8B are diagrams illustrating, in sequence, processes of themethod of manufacturing the GNR 200.

First, a precursor molecule 220 illustrated in FIG. 8A is prepared. Theprecursor molecule 220 is represented by the following structuralformula (2′). In the precursor molecule 220, X denotes a halogen atom,such as a Br atom, for example, that is bonded to a tenth carbon atom230 of anthracene 222. A ninth carbon atom 229 of the anthracene 222 isbonded to a porphine ring 221. In addition, the metal atom M₁ is bondedto a nitrogen (N) atom of the porphine ring 221. In other words, theprecursor molecule 220 is a metal complex. The metal atom M₁ may be theatom of Mg, Fe, Co, Ni, Ti, Cu, Zn, or the like, for example.

Next, the precursor molecules 220 are deposited on the (111) face of theheated catalyst metal substrate by vacuum deposition. A substrate madeof Au, Ag, Cu, or the like may be used for the catalyst metal substrate.The precursor molecules 220 may be deposited on the (110) face or the(100) face of the catalyst metal substrate by vacuum deposition, or maybe deposited on the crystal face of a higher index, such as the (788)face or the like, by vacuum deposition. When using the Au(111) face asthe depositing surface, the temperature of the Au(111) face, cleaned inultra-high vacuum, is maintained to approximately 200° C. toapproximately 300° C., for example, and the precursor molecules 220 aredeposited by the vacuum deposition. The amount that is deposited in thisstate is preferably adjusted to become approximately 1 molecular layer.In this temperature range, a dehalogenation reaction is generated inwhich the desorption of HBr occurs between the precursor molecules 220adsorbed on the Au(111) face, to promote polymerization of the precursormolecules 220 (or precursor molecule group). As a result, a polymer 240illustrated in FIG. 8B is formed.

Thereafter, the Au(111) face having the polymer 240 formed thereon isheated under vacuum to a high temperature of approximately 350° C. toapproximately 450° C., for example. In this high temperature range, adehydrocyclization reaction is generated in which desorption of H₂occurs within the precursor molecules 220 and between the precursormolecules 220 in the polymer 240, to promote aromatization. As a result,the GNR 200 according to the second embodiment is formed.

Hence, the GNR 200 according to the second embodiment can bemanufactured by the bottom-up synthesis.

Next, a method of manufacturing the precursor molecules 220 will bedescribed. FIG. 9 is a diagram illustrating the method of manufacturingthe precursor molecules used for manufacturing the GNR. First, in thismanufacturing method, the porphyrin 154 is prepared according to themethod of manufacturing the precursor molecules described above inconjunction with FIG. 5 . Next, the porphyrin 154 and a metallic salt ofthe metal atom M₁ are stirred in an organic solvent. As a result, themetal atom M₁ bonds to the N atom of the porphyrin 154, and a porphyrinmetal complex 255 is obtained. The stirring in the organic solvent maybe performed at room temperature or while applying heat.

Examples of the organic solvent that may be used includeN,N-dimethylformamide, dimethyl sulfoxide, acetic acid, pyridine, mixedsolvent of dichloromethane-methanol, mixed solvent ofchloroform-methanol, or the like, for example.

Examples of salts that may be used for the metallic salt include saltsof aluminum (Al), silicon (Si), phosphorus (P), scandium (Sc), titanium(Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel(Ni), zinc (Zn), gallium (Ga), germanium (Ge), arsenic (As), yttrium(Y), zirconium (Zr), molybdenum (Mo), ruthenium (Ru), rhodium (Rh),indium (In), palladium (Pd), platinum (Pt), tin (Sn), antimony (Sb),hafnium (Hf), tantalum (Ta), tungsten (W), osmium (Os), iridium (Ir),thallium (Tl), or the like, for example. More particularly, zincacetate, zinc nitrate, zinc sulfate, zing chloride, or the like may beused when manufacturing the precursor molecule of Zn using the metalatom M₁. In addition, copper (II) acetate, copper (II) nitrate, copper(II) sulfate, copper (II) chloride, or the like may be used whenmanufacturing the precursor molecule of Cu using the metal atom M₁.Further, nickel acetate, nickel nitrate, nickel sulfate, nickelchloride, or the like may be used when manufacturing the precursormolecule of Ni using the metal atom M₁. Titanocene dichloride, titaniumoxide bisacetylacetonate, or the like may be used when manufacturing theprecursor molecule of Ti using the metal atom M₁. However, when usingtitanium oxide bis acetylacetonate, the metal atom M₁ becomes an oxideof Ti (TiO), and not Ti itself. Iron acetate, iron sulfate, ironchloride, or the like may be used when manufacturing the precursormolecule of Fe using the metal atom M₁. Magnesium acetate, magnesiumnitrate, magnesium sulfate, magnesium chloride, or the like may be usedwhen manufacturing the precursor molecule of Mg using the metal atom M₁.However, the metallic salt is of course not limited to salts describedabove.

When manufacturing the precursor molecule 220, the porphyrin 154 inwhich each of the integers p, q, r, s, t, and u is 1, each of the R¹,R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ is H, and the alkyl group A is H.

In the following description, the GNR in which structures represented bythe above-mentioned structural formula (10) are arranged, may also bereferred to as a porphyrin metal complex GNR.

In the above-mentioned structural formulas (8) and (10), the integers p,q, r, s, t, and u may be mutually independent and be integers greaterthan or equal to 2, the R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ may bemutually independent and be any one of a substituent, an alkyl moiety, aphenyl moiety, and a halogen atom, and the alkyl group A may be an arylgroup.

Third Embodiment

Next, a third embodiment will be described. The third embodiment relatesto the GNR. FIG. 10 is a diagram illustrating the GNR according to thethird embodiment.

A GNR 300 according to the third embodiment includes a porphyrin GNRpart 301, and a porphyrin metal complex GNR part 302, as illustrated inFIG. 10 . The porphyrin GNR part 301 includes a structure in which aplurality of sub-units 113 are arranged. In other words, the porphyrinGNR part 301 has a structure in which h is an integer greater than orequal to 1, each of the integers p, q, r, s, t, and u is 1, each of theR¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ is H, and the alkyl group A is H inthe following structural formula (14). The porphyrin metal complex GNRpart 302 includes a structure in which a plurality of sub-units 213 arearranged. In other words, the porphyrin metal complex GNR part 302 has astructure in which g is an integer greater than or equal to 1, each ofthe integers p, q, r, s, t, and u is 1, each of the R¹, R², R³, R⁴, R⁵,R⁶, R⁷, and R⁸ is H, and the alkyl group A is H in the followingstructural formula (13). The sub-unit 213 includes, in a part thereof,the structure presented by the above-mentioned structural formula (10).The sub-unit 113 includes, in a part thereof, the structure presented bythe above-mentioned structural formula (11). The porphyrin metal complexGNR part 302 is an example of a first unit, and the porphyrin GNR part301 is an example of a second unit. The porphyrin GNR part 301 and theporphyrin metal complex GNR part 302 are bonded to each other by acarbon-to-carbon bonding at respective ends of the porphyrin GNR part301 and the porphyrin metal complex GNR part 302. The GNR 300 includesthe chemical structure of porphyrin and the chemical structure of themetal complex of porphyrin.

According to the third embodiment, it is possible to form aheterojunction between the porphyrin GNR part 301 and the porphyrinmetal complex GNR part 302 that have different electron states. Hence,the GNR 300 can contribute to producing various electron states, and theGNR 300 has good application properties with respect to varioussemiconductor devices.

Next, a method of manufacturing the GNR 300 will be described. FIG. 11Aand FIG. 11B are diagrams illustrating, in sequence, processes of themethod of manufacturing the GNR 300.

First, as illustrated in FIG. 11A, the GNR 100 according to the firstembodiment is formed on the catalyst metal substrate. Next, asillustrated in FIG. 11B, a mask 350, that exposes a region where theporphyrin metal complex GNR part 302 of the GNR 100 is to be formed, andcovers the remaining region, is formed on the GNR 100. Thereafter, theGNR 100 having the mask 350 formed thereon, is immersed into an organicsolvent having dissolved therein the metallic salt of the metal atom M₁to be included in the porphyrin metal complex GNR part 302, togetherwith the catalyst metal substrate, and the organic solvent is stirred.As a result, the metal atom M₁ bonds to the N atom of the porphine ring111, to form the porphyrin metal complex GNR part 302, at the region ofthe GNR 100 exposed from the mask 350. In addition, the remaining regionof the GNR 100 becomes the porphyrin GNR part 301. The organic solventmay be stirred at room temperature, or may be stirred while applyingheat. Then, the catalyst metal substrate is extracted from the organicsolvent, together with the porphyrin GNR part 301 and the porphyrinmetal complex GNR part 302, and the mask 350 is removed.

Hence, the GNR 300 according to the third embodiment can be manufacturedby the processes described heretofore.

For example, a metallic salt similar to the metallic salt used by themethod of manufacturing the precursor molecule described above inconjunction with FIG. 9 , may be used for the metallic salt of the metalatom M₁ included in the porphyrin metal complex GNR part 302. A materialforming the mask 350 is not particularly limited, and the kind oforganic solvent used is not particularly limited. Preferably, thematerial used for the mask 350 is polymethyl methacrylate (PMMA), andthe kind of organic solvent used is an aqueous solution of acetic acid.

According to the third embodiment, the porphyrin metal complex GNR part302 and the porphyrin GNR part 301 have structures in which each of theintegers p, q, r, s, t, and u is 1, each of the R¹, R², R³, R⁴, R⁵, R⁶,R⁷, and R⁸ is H, and the alkyl group A is H in the above-mentionedstructural formulas (13) and (14), respectively. However, in theabove-mentioned structural formulas (13) and (14), the integers p, q, r,s, t, and u may be mutually independent and be integers greater than orequal to 2, the R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ may be mutuallyindependent and be any one of a substituent, an alkyl moiety, a phenylmoiety, and a halogen atom, and the alkyl group A may be an aryl group.The porphyrin metal complex GNR part 302 and the porphyrin GNR part 301may be arranged periodically.

Fourth Embodiment

Next, a fourth embodiment will be described. The fourth embodimentrelates to the GNR. FIG. 12 is a diagram illustrating the GNR accordingto the fourth embodiment.

A GNR 400 according to the fourth embodiment includes a porphyrin metalcomplex GNR part 401, and a porphyrin metal complex GNR part 402, asillustrated in FIG. 12 . The porphyrin metal complex GNR part 401includes a structure in which a plurality of sub-units 413 a, eachincluding 2 rows of anthracene 412 bonded to a porphine ring 411 a thatincludes a metal atom M₁, are arranged. In other words, the porphyrinmetal complex GNR part 401 has a structure in which g is an integergreater than or equal to 1, each of the integers p, q, r, s, t, and u is1, each of the R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ is H, and the alkylgroup A is H in the above-mentioned structural formula (13). Theporphyrin metal complex GNR part 402 includes a structure in which aplurality of sub-units 413 b, each including 2 rows of anthracene 412bonded to a porphine ring 411 b that includes a metal atom M₂, arearranged. In other words, the porphyrin metal complex GNR part 402 has astructure in which h is an integer greater than or equal to 1, each ofthe integers p, q, r, s, t, and u is 1, each of the R¹, R², R³, R⁴, R⁵,R⁶, R⁷, and R⁸ is H, and the alkyl group A is H in the above-mentionedstructural formula (15). The sub-unit 413 a includes, in a part thereof,the structure represented by the above-mentioned structural formula(10). The sub-unit 413 b includes, in a part thereof, the structurerepresented by the above-mentioned structural formula (12). The metalatoms M₁ and M₂ are selected from Mg, Fe, Co, Ni, Ti, Cu, Zn, or thelike, for example, and are mutually different. The metal atoms M₁ and M₂are not limited to these elements, as long as the metal atoms M₁ and M₂can be coordinated in a porphyrin ring. The porphyrin metal complex GNRpart 401 is an example of a first unit, and the porphyrin metal complexGNR part 402 is an example of a second unit. The porphyrin metal complexGNR part 401 and the porphyrin metal complex GNR part 402 are bonded toeach other by a carbon-to-carbon bonding at respective ends of theporphyrin metal complex GNR part 401 and the porphyrin metal complex GNRpart 402. The GNR 400 includes the chemical structure of the metalcomplex of porphyrin.

According to the fourth embodiment, it is possible to form aheterojunction between the porphyrin metal complex GNR part 401 and theporphyrin metal complex GNR part 402. Hence, the GNR 400 can contributeto producing various electron states, and the GNR 400 has goodapplication properties with respect to various semiconductor devices.

Next, a method of manufacturing the GNR 400 will be described. FIG. 13Aand FIG. 13B are diagrams illustrating, in sequence, processes of themethod of manufacturing the GNR 400. In this example, it is assumed forthe sake of convenience that the metal atom M₂ more easily bonds to theN atom of the porphine ring than the metal atom M₁.

First, as illustrated in FIG. 13A, a porphyrin metal complex GNR 460having the metal atom M1 bonded to the N atom of the porphine ring, isformed on the catalyst metal substrate according to the method ofmanufacturing the GNR 200. Next, as illustrated in FIG. 13B, a mask 450,that exposes a region where a porphyrin metal complex GNR part 402 ofthe porphyrin metal complex GNR 460 is to be formed, and covers theremaining region, is formed on the porphyrin metal complex GNR 460.Thereafter, the porphyrin metal complex GNR 460 having the mask 450formed thereon, is immersed into an organic solvent having dissolvedtherein the metallic salt of the metal atom M₂ to be included in theporphyrin metal complex GNR part 402, together with the catalyst metalsubstrate, and the organic solvent is stirred. As a result, the metalatom M₂ bonds to the N atom in place of the metal atom M₁, to form theporphyrin metal complex GNR part 402, at the region of the porphyrinmetal complex GNR 460 exposed from the mask 450. In addition, theremaining region of the porphyrin metal complex GNR 460 becomes theporphyrin metal complex GNR part 401. The organic solvent may be stirredat room temperature, or may be stirred while applying heat. Then, thecatalyst metal substrate is extracted from the organic solvent, togetherwith the porphyrin metal complex GNR part 401 and the porphyrin metalcomplex GNR part 402, and the mask 450 is removed.

Hence, the GNR 400 according to the fourth embodiment can bemanufactured by the processes described heretofore.

For example, a metallic salt similar to the metallic salt used by themethod of manufacturing the precursor molecule described above inconjunction with FIG. 9 , may be used for the metallic salt of the metalatom M₂ included in the porphyrin metal complex GNR part 402. A materialforming the mask 450 is not particularly limited, and the kind oforganic solvent used is not particularly limited. Preferably, thematerial used for the mask 450 is PMMA, and the kind of organic solventused is an aqueous solution of acetic acid.

In a case where the metal atom M₁ more easily bonds to the N atom of theporphine ring than the metal atom M₂, a porphyrin metal complex GNRhaving the metal atom M₂ bonded to the porphine ring may be prepared,and a part of the metal atoms M₂ may be substituted by the metal atomsM₁. In this case, a metallic salt similar to the metallic salt used bythe method of manufacturing the precursor molecule described above inconjunction with FIG. 9 , may also be used for the metallic salt of themetal atom M₁ included in the porphyrin metal complex GNR part 401.

According to the fourth embodiment, the porphyrin metal complex GNR part401 and the porphyrin metal complex GNR part 402 have structures inwhich each of the integers p, q, r, s, t, and u is 1, each of the R¹,R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ is H, and the alkyl group A is H in theabove-mentioned structural formulas (13) and (15), respectively.However, in the above-mentioned structural formulas (13) and (15), theintegers p, q, r, s, t, and u may be mutually independent and beintegers greater than or equal to 2, the R¹, R², R³, R⁴, R⁵, R⁶, R⁷, andR⁸ may be mutually independent and be any one of a substituent, an alkylmoiety, a phenyl moiety, and a halogen atom, and the alkyl group A maybe an aryl group. The porphyrin metal complex GNR part 401 and theporphyrin metal complex GNR part 402 may be arranged periodically.

Fifth Embodiment

Next, a fifth embodiment will be described. The fifth embodiment relatesto a nanoribbon including porphyrin as sub-units. FIG. 14 is a diagramillustrating the nanoribbon according to the fifth embodiment.

A nanoribbon 500 according to the fifth embodiment includes a porphyrinnanoribbon part 501, and a porphyrin metal complex nanoribbon part 502,as illustrated in FIG. 14 . The porphyrin nanoribbon part 501 includes astructure in which sub-units of a porphine ring 511 a are arranged. Theporphyrin metal complex nanoribbon part 502 includes a structure inwhich sub-units of a porphine ring 511 b are arranged. A metal atom M₁is bonded to the N atom of the porphine ring 511 b. The porphyrin metalcomplex nanoribbon part 502 is an example of a first unit, and theporphyrin nanoribbon part 501 is an example of a second unit. Theporphyrin nanoribbon part 501 and the porphyrin metal complex nanoribbonpart 502 are bonded to each other by a carbon-to-carbon bonding atrespective ends of the porphyrin nanoribbon part 501 and the porphyrinmetal complex nanoribbon part 502. The nanoribbon 500 includes thechemical structure of porphyrin and the chemical structure of the metalcomplex of porphyrin.

According to the fifth embodiment, it is possible to form aheterojunction between the porphyrin nanoribbon part 501 and theporphyrin metal complex nanoribbon part 502. Hence, the nanoribbon 500can contribute to producing various electron states, and the nanoribbon500 has good application properties with respect to varioussemiconductor devices.

Next, a method of manufacturing the nanoribbon 500 will be described.FIG. 15A and FIG. 15B are diagrams illustrating, in sequence, processesof the method of manufacturing the nanoribbon 500.

First, as illustrated in FIG. 15A, a porphyrin nanoribbon 560 is formedon a catalyst metal substrate. The porphyrin nanoribbon 560 can besynthesized on the catalyst metal substrate by polymerizing theporphyrin 154 in which each of the integers p, q, r, s, t, and u is 0,and the alkyl group A is H, for example. The porphyrin nanoribbon 560 isdescribed in Akihiko Tsuda et al., “Fully Conjugated Porphyrin Tapeswith Electronic Absorption Bands That Reach into Infrared”, Science,Vol. 293, 6 Jul. 2001, pp. 79-82, and Tien Quang Nguyen et al.,“Adsorption of diatomic molecules on iron tape-porphyrin: A comparativestudy”, Physical Review, B 77, 195307, 2008, pp. 1-7, for example. Next,as illustrated in FIG. 15B, a mask 550, that exposes a region where theporphyrin metal complex nanoribbon part 502 of the porphyrin nanoribbon560 is to be formed, and covers the remaining region, is formed on theporphyrin nanoribbon 560. Thereafter, the porphyrin nanoribbon 560having the mask 550 formed thereon, is immersed into an organic solventhaving dissolved therein the metallic salt of the metal atom M₁ to beincluded in the porphyrin metal complex nanoribbon part 502, togetherwith the catalyst metal substrate, and the organic solvent is stirred.As a result, the metal atom M₁ bonds to the N atom of the porphine ring,to form the porphyrin metal complex nanoribbon part 502, at the regionof the porphyrin nanoribbon 560 exposed from the mask 550. In addition,the remaining region of the porphyrin nanoribbon 560 becomes theporphyrin nanoribbon part 501. The organic solvent may be stirred atroom temperature, or may be stirred while applying heat. Then, thecatalyst metal substrate is extracted from the organic solvent, togetherwith the porphyrin nanoribbon part 501 and the porphyrin metal complexnanoribbon part 502, and the mask 550 is removed.

Hence, the nanoribbon 500 according to the fifth embodiment can bemanufactured by the processes described heretofore.

A material forming the mask 550 is not particularly limited, and thekind of organic solvent used is not particularly limited. Preferably,the material used for the mask 550 is PMMA, and the kind of organicsolvent used is an aqueous solution of acetic acid.

Sixth Embodiment

Next, a sixth embodiment will be described. The sixth embodiment relatesto the nanoribbon including the porphyrin as the sub-units. FIG. 16 is adiagram illustrating the nanoribbon according to the sixth embodiment.

A nanoribbon 600 according to the sixth embodiment includes a porphyrinmetal complex nanoribbon part 601, and a porphyrin metal complexnanoribbon part 602, as illustrated in FIG. 16 . The porphyrin metalcomplex nanoribbon part 601 includes a structure in which sub-units of aporphine ring 611 a are arranged. The porphyrin metal complex nanoribbonpart 602 has a structure in which sub-units of a porphine ring 611 b arearranged. A metal atom M₁ is bonded to the N atom of the porphine ring611 a, and a metal atom M₂ is bonded to the N atom of the porphine ring611 b. The porphyrin metal complex nanoribbon part 601 is an example ofa first unit, and the porphyrin metal complex nanoribbon part 602 is anexample of a second unit. The porphyrin metal complex nanoribbon part601 and the porphyrin metal complex nanoribbon part 602 are bonded toeach other by a carbon-to-carbon bonding at respective ends of theporphyrin metal complex nanoribbon part 601 and the porphyrin metalcomplex nanoribbon part 602. The nanoribbon 600 includes the chemicalstructure of the metal complex of porphyrin.

According to the sixth embodiment, it is possible to form aheterojunction between the porphyrin metal complex nanoribbon part 601and the porphyrin metal complex nanoribbon part 602. Hence, thenanoribbon 600 can contribute to producing various electron states, andthe nanoribbon 600 has good application properties with respect tovarious semiconductor devices.

Next, a method of manufacturing the nanoribbon 600 will be described.FIG. 17A and FIG. 17B are diagrams illustrating, in sequence, processesof the method of manufacturing the nanoribbon 600. In this example, itis assumed for the sake of convenience that the metal atom M₂ moreeasily bonds to the N atom of the porphine ring than the metal atom M₁.

First, as illustrated in FIG. 17A, a porphyrin metal complex nanoribbon660 is formed on a catalyst metal substrate. The porphyrin nanoribbon660 can be synthesized on the catalyst metal substrate by polymerizingthe porphyrin metal complex 255 in which each of the integers p, q, r,s, t, and u is 0, and the alkyl group A is H, for example. Next, asillustrated in FIG. 17B, a mask 650, that exposes a region where aporphyrin metal complex nanoribbon part 602 of the porphyrin metalcomplex nanoribbon 660 is to be formed, and covers the remaining region,is formed on the porphyrin metal complex nanoribbon 660. Thereafter, theporphyrin metal complex nanoribbon 660 having the mask 650 formedthereon, is immersed into an organic solvent having dissolved thereinthe metallic salt of the metal atom M₂ to be included in the porphyrinmetal complex nanoribbon part 602, together with the catalyst metalsubstrate, and the organic solvent is stirred. As a result, the metalatom M₂ bonds to the N atom in place of the metal atom M₁, to form theporphyrin metal complex nanoribbon part 602, at the region of theporphyrin metal complex nanoribbon 660 exposed from the mask 650. Inaddition, the remaining region of the porphyrin metal complex nanoribbon660 becomes the porphyrin metal complex nanoribbon part 601. The organicsolvent may be stirred at room temperature, or may be stirred whileapplying heat. Then, the catalyst metal substrate is extracted from theorganic solvent, together with the porphyrin metal complex nanoribbonpart 601 and the porphyrin metal complex nanoribbon part 602, and themask 650 is removed.

Hence, the nanoribbon 600 according to the sixth embodiment can bemanufactured by the processes described heretofore.

A material forming the mask 650 is not particularly limited, and thekind of organic solvent used is not particularly limited. Preferably,the material used for the mask 650 is PMMA, and the kind of organicsolvent used is an aqueous solution of acetic acid.

In a case where the metal atom M₁ more easily bonds to the N atom of theporphine ring than the metal atom M₂, a porphyrin metal complexnanoribbon having the metal atom M₂ bonded to the porphine ring may beprepared, and a part of the metal atoms M₂ may be substituted by themetal atoms M₁.

Seventh Embodiment

Next, a seventh embodiment will be described. The seventh embodimentrelates to a semiconductor device including the GNR. FIG. 18A and FIG.18B respectively are a plan view and a cross sectional view illustratingthe semiconductor device according to the seventh embodiment. FIG. 18Bcorresponds to the cross sectional view along a line I-I in FIG. 18A.

A semiconductor device 700 according to the seventh embodiment includesa silicon substrate 701, a GNR 702, a gate insulating layer 703, a gateelectrode 704, a source electrode 705, and a drain electrode 706, asillustrated in FIG. 18A and FIG. 18B. The GNR 702 is provided on thesilicon substrate 701. The source electrode 705 contacts one end (firstend) of the GNR 702 on the silicon substrate 701, and the drainelectrode 706 contacts another end (second end) of the GNR 702 on thesilicon substrate 701. The gate insulating layer 703 is provided on theGNR 702 between the source electrode 705 and the drain electrode 706.The gate electrode 704 is provided on the gate insulating layer 703.

The GNR 702 includes a porphyrin GNR part 702 a under the gateinsulating layer 703, a porphyrin metal complex GNR part 702 b arrangedcloser to the source electrode 705 than the porphyrin GNR part 702 a,and a porphyrin metal complex GNR part 702 b arranged closer to thedrain electrode 706 than the porphyrin GNR part 702 a. The porphyrin GNRpart 702 a and the porphyrin metal complex GNR part 702 b are bonded toeach other by a carbon-to-carbon bonding at the respective first andsecond ends of the porphyrin GNR part 702 a. The porphyrin metal complexGNR part 702 b includes a porphine ring, and a Cu atom is bonded to theN atom of the porphine ring. In other words, the porphyrin GNR part 702a includes the chemical structure of porphyrin, and the porphyrin metalcomplex GNR part 702 b includes the chemical structure of porphyrinmetal complex.

FIG. 19 is a diagram illustrating a band structure of the GNR 702. Asillustrated in FIG. 19 , in the porphyrin GNR part 702 a, the Fermilevel E_(F) is located between a top of a conduction band and a bottomof a valence band thereof. On the other hand, in the porphyrin metalcomplex GNR part 702 b, the Fermi level E_(F) is higher than the bottomof the valence band thereof. Accordingly, the porphyrin GNR part 702 aexhibits properties of the i-type semiconductor, the porphyrin metalcomplex GNR part 702 b exhibits properties of the n-type semiconductor,and the GNR 702 includes a nin heterojunction.

Hence, the semiconductor device 700 is an example of a top-gate typeField Effect Transistor (FET) having the nin structure and the GNR 702as a channel layer.

An insulating material, such as silicon oxide (SiO₂) or the like, may beused for the gate insulating layer 703. A metal material, such astitanium (Ti), chromium (Cr), cobalt (Co), nickel (Ni), palladium (Pd),aluminum (Al), copper (Cu), silver (Ag), platinum (Pt), gold (Au), orthe like, may be used for the gate electrode 704, the source electrode705, and the drain electrode 706.

According to the seventh embodiment, it is possible to obtain a FEThaving a simple structure and a small band gap. In addition, by changingthe metal atom included in the porphyrin metal complex GNR part 702 b toa Ni atom or the like having the Fermi level E_(F) that is higher thanthe bottom of the valence band thereof, it becomes possible to adjustthe band gap while simultaneously achieving the nin heterojunction.

Next, a method of manufacturing the semiconductor device 700 will bedescribed. FIG. 20A through FIG. 20D are cross sectional viewsillustrating, in sequence, processes of the method of manufacturing thesemiconductor device 700.

First, as illustrated in FIG. 20A, the porphyrin GNR 760 is provided onthe silicon substrate 701. For example, the porphyrin GNR 760 may beformed on a catalyst metal substrate by bottom-up synthesis, and thentransferred onto the silicon substrate 701 using a mending tape or thelike.

Next, as illustrated in FIG. 20B, the gate insulating layer 703 and thegate electrode 704 are formed on the silicon substrate 701, so as tocover a region where the porphyrin GNR part 702 a of the porphyrin GNR760 is to be formed. When forming the gate insulating layer 703 and thegate electrode 704, a resist is first patterned using photolithography,to form a resist mask having openings in regions where the gateinsulating layer 703 and the gate electrode 704 are to be formed. Then,an Al layer having a thickness of approximate 1 nm, for example, isformed on the resist mask, including the inside of the openings in theresist mask, by a deposition method such as sputtering or the like. ThisAl layer is used as a seed layer, to deposit an insulating layer of HfO₂or the like, using Atomic Layer Deposition (ALD), to deposit aninsulating layer on the Al layer. Thereafter, a metal layer is depositedon the insulating layer using vapor deposition, sputtering, or the like.The metal layer may have a laminated structure including a Ti layer, anda Au layer formed on the Ti layer, for example. Finally, the resistmask, and the insulating layer and the metal layer provided on theresist mask, are removed using lift-off, for example. As a result, it ispossible to form the gate insulating layer 703 and the gate electrode704.

Thereafter, as illustrated in FIG. 20C, the silicon substrate 701 havingthe porphyrin GNR 760, the gate insulating layer 703, and the gateelectrode 704 formed thereon, is immersed into an organic solvent havingdissolved therein the metallic salt of Cu, and the organic solvent isstirred. As a result, the Cu atom bonds to the N atom of the porphinering, as the metal atom M₁, at the regions of the porphyrin GNR 760where the gate insulating layer 703 and the gate electrode 704 areexposed from the porphyrin GNR 760. Hence, the GNR 702, including theporphyrin GNR part 702 a and the porphyrin metal complex GNR part 702 b,is formed. The kind of organic solvent used may be an aqueous solutionof acetic acid, for example.

Next, as illustrated in FIG. 20D, the source electrode 705 that contactsthe first end of the GNR 702, and the drain electrode 706 that contactsthe second end of the GNR 702, are formed on the silicon substrate 701.When forming the source electrode 705 and the drain electrode 706, aresist is first patterned using photolithography, to form a resist maskhaving openings in regions where the source electrode 705 and the drainelectrode 706 are to be formed. Then, a metal layer is deposited on theresist mask, including the inside of the openings in the resist mask,using vapor deposition, sputtering, or the like. The metal layer mayhave a laminated structure including a Ti layer, and a Au layer formedon the Ti layer, for example. Finally, the resist mask, and the metallayer provided on the resist mask, are removed using lift-off, forexample. As a result, it is possible to form the source electrode 705and the drain electrode 706.

Hence, the semiconductor device 700 according to the seventh embodimentcan be manufactured by the processes described heretofore.

Eighth Embodiment

Next, an eighth embodiment will be described. The eighth embodimentrelates to the semiconductor device including the GNR. FIG. 21A and FIG.21B respectively are a plan view and a cross sectional view illustratingthe semiconductor device according to the eighth embodiment. FIG. 21Bcorresponds to the cross sectional view along a line I-I in FIG. 21A.

A semiconductor device 800 according to the eighth embodiment includes aGNR 802 in place of the GNR 702, as illustrated in FIG. 21A and FIG.21B. Otherwise, the structure of the eight embodiment is the same as thestructure of the seventh embodiment. The GNR 802 includes a porphyrinmetal complex GNR part 802 a under the gate insulating layer 703, aporphyrin metal complex GNR part 802 b arranged closer to the sourceelectrode 705 than the porphyrin metal complex GNR part 802 a, and aporphyrin metal complex GNR part 802 b arranged closer to the drainelectrode 706 than the porphyrin metal complex GNR part 802 a. Theporphyrin metal complex GNR part 802 a and the porphyrin metal complexGNR part 802 b are bonded to each other by a carbon-to-carbon bonding atthe respective first and second ends of the porphyrin metal complex GNRpart 802 a. The porphyrin metal complex GNR part 802 a includes aporphine ring, and a Zn atom is bonded to the N atom of the porphinering. The porphyrin metal complex GNR parts 802 b include a porphinering, and a Cu atom is bonded to the N atom of the porphine ring.

FIG. 22 is a diagram illustrating a band structure of the GNR 802. Asillustrated in FIG. 22 , in the porphyrin metal complex GNR part 802 a,the Fermi level E_(F) is located between a top of a conduction band anda bottom of a valence band thereof. On the other hand, in the porphyrinmetal complex GNR part 802 b, the Fermi level E_(F) is higher than thebottom of the valence band thereof. Accordingly, the porphyrin metalcomplex GNR part 802 a exhibits properties of the i-type semiconductor,the porphyrin metal complex GNR part 802 b exhibits properties of then-type semiconductor, and the GNR 802 includes a nin heterojunction.

Hence, the semiconductor device 800 is an example of a top-gate type FEThaving the nin structure and the GNR 802 as the channel layer.

According to the eighth embodiment, it is possible to obtain a FEThaving a simple structure and a small band gap. In addition, by changingthe metal atom included in the porphyrin metal complex GNR part 802 b toa Ni atom or the like having the Fermi level E_(F) that is higher thanthe bottom of the valence band thereof, it becomes possible to adjustthe band gap while simultaneously achieving the nin heterojunction.Further, by changing the metal atom included in the porphyrin metalcomplex GNR part 802 a to another atom having the Fermi level E_(F) thatis located between the top of the conduction band and the bottom of thevalence band thereof, it becomes possible to adjust the band gap whilesimultaneously achieving the nin heterojunction.

Next, a method of manufacturing the semiconductor device 800 will bedescribed. FIG. 23A through FIG. 23D are cross sectional viewsillustrating, in sequence, processes of the method of manufacturing thesemiconductor device 800.

First, as illustrated in FIG. 23A, the porphyrin metal complex GNR 860in which the Zn atom is bonded to the N atom of the porphine ring, isprovided on the silicon substrate 701. For example, the porphyrin metalcomplex GNR 860 may be formed on a catalyst metal substrate by bottom-upsynthesis, and then transferred onto the silicon substrate 701 using amending tape or the like.

Next, as illustrated in FIG. 23B, the gate insulating layer 703 and thegate electrode 704 are formed on the silicon substrate 701, so as tocover a region where the porphyrin metal complex GNR part 802 a of theporphyrin GNR 860 is to be formed.

Thereafter, as illustrated in FIG. 23C, the silicon substrate 701 havingthe porphyrin metal complex GNR 860, the gate insulating layer 703, andthe gate electrode 704 formed thereon, is immersed into an organicsolvent having dissolved therein the metallic salt of Cu, and theorganic solvent is stirred. As a result, the Cu atom bonds to the N atomof the porphine ring, as the metal atom M₂ in place of the Zn atom, atthe regions of the porphyrin metal complex GNR 860 where the gateinsulating layer 703 and the gate electrode 704 are exposed from theporphyrin metal complex GNR 860. Hence, the GNR 802, including theporphyrin metal complex GNR part 802 a and the porphyrin metal complexGNR part 802 b, is formed. The kind of organic solvent used may be anaqueous solution of acetic acid, for example.

Next, as illustrated in FIG. 23D, the source electrode 705 that contactsthe first end of the GNR 802, and the drain electrode 706 that contactsthe second end of the GNR 802, are formed on the silicon substrate 701.

Hence, the semiconductor device 800 according to the eighth embodimentcan be manufactured by the processes described heretofore.

In each of the embodiments described above, acene included in the unitsis not limited to anthracene, and the acene may be naphthalene,tetracene, or the like. In addition, in each of the nanoribbonsaccording to the embodiments, the terminal group is not particularlylimited. For example, the terminal group of the nanoribbon synthesizedfrom the precursor molecule illustrated in FIG. 4A, may include ahydrogen or halogen atom bonded with respect to the plurality of carbonatoms located at the end of the nanoribbon, similar to the precursormolecule of FIG. 4A, or alternatively, the hydrogen atom may be bondedto all of plurality of carbon atoms located at the end of thenanoribbon. In the seventh and eighth embodiments, a porphyrinnanoribbon may be used in place of the GNR.

The usage of the semiconductor devices described heretofore is notparticularly limited. For example, the semiconductor devices may be usedfor high-power amplifiers for wireless base stations, high-poweramplifiers for mobile phone base stations, semiconductor elements forservers, semiconductor elements for personal computers, on-boardIntegrated Circuits (ICs) for vehicles, motor driving transistors forelectric vehicles, or the like.

According to each of the embodiments described above, it is possible toobtain various electron states.

Although the embodiments are numbered with, for example, “first,”“second,” “third,” “fourth,” “fifth,” “sixth,” “seventh,” or “eighth,”the ordinal numbers do not imply priorities of the embodiments. Manyother variations and modifications will be apparent to those skilled inthe art.

All examples and conditional language recited herein are intended forpedagogical purposes to aid the reader in understanding the inventionand the concepts contributed by the inventor to furthering the art, andare to be construed as being without limitation to such specificallyrecited examples and conditions, nor does the organization of suchexamples in the specification relate to a showing of the superiority andinferiority of the invention. Although the embodiments of the presentinvention have been described in detail, it should be understood thatthe various changes, substitutions, and alterations could be made heretowithout departing from the spirit and scope of the invention.

What is claimed is:
 1. A nanoribbon comprising: a structure represented by a structural formula (8), where M₁ is a metal atom, g, p, q, r, s, t, and u are mutually independent and are integers greater than or equal to 1, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ are mutually independent and are one of a hydrogen atom, a substituent, an alkyl moiety, a phenyl moiety, and a halogen atom, the substituent is selected from a group consisting of a hydroxyl group, a nitro group, an amino group, a formyl group, a carboxyl group, and a sulfonyl group, and A is a hydrogen atom or an aryl group


2. A nanoribbon comprising: a first unit having a structure including an arrangement of a plurality of first sub-units respectively including a structure represented by a structural formula (10); and a second unit having a structure including an arrangement of a plurality of second sub-units respectively including a structure represented by a structural formula (11), wherein the first unit and the second unit are mutually bonded by a carbon-to-carbon bonding between an end of the first unit and an end of the second unit, wherein M₁ is a metal atom, and A is a hydrogen atom or an aryl group,

wherein the first unit has the structure represented by a structural formula (13) in which g, p, q, r, s, t, and u are mutually independent and are integers greater than or equal to 1, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ are mutually independent and are one of a hydrogen atom, a substituent, an alkyl moiety, a phenyl moiety, and a halogen atom, the substituent is selected from a group consisting of a hydroxyl group, a nitro group, an amino group, a formyl group, a carboxyl group, and a sulfonyl group, and A is a hydrogen atom or an aryl group, and

wherein the second unit has the structure represented by a structural formula (14) in which h, p, q, r, s, t, and u are mutually independent and are integers greater than or equal to 1, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ are mutually independent and are one of a hydrogen atom, a substituent, an alkyl moiety, a phenyl moiety, and a halogen atom, the substituent is selected from a group consisting of a hydroxyl group, a nitro group, an amino group, a formyl group, a carboxyl group, and a sulfonyl group, and A is a hydrogen atom or an aryl group


3. The nanoribbon as claimed in claim 2, wherein at least the plurality of first sub-units or the plurality of second sub-units further include at least one structure represented by a structural formula (16), p, r, and s are mutually independent and are integers greater than or equal to 1, R¹, R², R³, and R⁴ are mutually independent and are one of a hydrogen atom, a substituent, an alkyl moiety, a phenyl moiety, and a halogen atom, and the substituent is selected from a group consisting of a hydroxyl group, a nitro group, an amino group, a formyl group, a carboxyl group, and a sulfonyl group


4. The nanoribbon as claimed in claim 2, wherein the first unit and the second unit are periodically arranged.
 5. A nanoribbon comprising: a first unit having a structure including an arrangement of a plurality of first sub-units respectively including a structure represented by a structural formula (10); and a second unit having a structure including an arrangement of a plurality of second sub-units respectively including a structure represented by a structural formula (12), wherein the first unit and the second unit are mutually bonded by a carbon-to-carbon bonding between an end of the first unit and an end of the second unit, wherein M₁ and M₂ are mutually different metal atoms, and A is a hydrogen atom or an aryl group,

wherein the first unit has the structure represented by a structural formula (13) in which g, p, q, r, s, t, and u are mutually independent and are integers greater than or equal to 1, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ are mutually independent and are one of a hydrogen atom, a substituent, an alkyl moiety, a phenyl moiety, and a halogen atom, the substituent is selected from a group consisting of a hydroxyl group, a nitro group, an amino group, a formyl group, a carboxyl group, and a sulfonyl group, and A is a hydrogen atom or an aryl group, and

wherein the second unit has the structure represented by a structural formula (15) in which h, p, q, r, s, t, and u are mutually independent and are integers greater than or equal to 1, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ are mutually independent and are one of a hydrogen atom, a substituent, an alkyl moiety, a phenyl moiety, and a halogen atom, the substituent is selected from a group consisting of a hydroxyl group, a nitro group, an amino group, a formyl group, a carboxyl group, and a sulfonyl group, and A is a hydrogen atom or an aryl group


6. The nanoribbon as claimed in claim 5, wherein at least the plurality of first sub-units or the plurality of second sub-units further include at least one structure represented by a structural formula (16), p, r, and s are mutually independent and are integers greater than or equal to 1, R¹, R², R³, and R⁴ are mutually independent and are one of a hydrogen atom, a substituent, an alkyl moiety, a phenyl moiety, and a halogen atom, and the substituent is selected from a group consisting of a hydroxyl group, a nitro group, an amino group, a formyl group, a carboxyl group, and a sulfonyl group


7. The nanoribbon as claimed in claim 5, wherein the first unit and the second unit are periodically arranged. 